This invention relates to flexible gear couplings used to connect rotating shafts in machinery. It relates particularly to a means of inspecting the gears used in such couplings.
Flexible couplings are commonly used for connecting rotary shafts in machinery such as the shafts connecting an electric motor to a pump. Such couplings are very useful in prolonging the life of the machinery since the repeated flexing of rigidly coupled rotary shafts, regardless of how slightly they are misaligned, can produce severe stresses in the shafts, the bearings and the machinery. Also excessive stresses can be incurred when the normal axial movement of rigidly coupled rotary shafts is constrained. A flexible coupling on the shafts permits such excessive stresses by compensating for any misalignment of the shafts or axial shaft movement, while at the same time transmitting the torque from one shaft to the other.
Gear type flexible couplings are manufactured by many manufacturers of mechanical power transmission equipment and are widely used in industry. The gear-type coupling consists of two similar hubs with external gear teeth and a floating sleeve assembly with internal gear teeth. The hubs are fitted to the ends of the driving and driven shafts, and as the driving shaft rotates, the driving hub gear teeth engage the internal gear teeth of the floating sleeve assembly so that the entire coupling rotates as a unit.
Flexible gear couplings, like any other piece of rotating machinery, are subject to excessive wear if not properly lubricated and maintained. In addition, flexible gear couplings are frequently subjected to starting and stopping impact loads that can damage the gears, if excessive. As a result flexible gear couplings need to be regularly inspected and repaired or replaced if necessary. Regular inspections are often required by OSHA regulations. The sealed sleeve over the hubs prevents a visual inspection of the conditions of the gears on the hubs and the gears in the sleeve. An inspection requires the removal of the motor or prime mover and a complete disassembly of the flexible gear coupling, which is time-consuming and expensive.